Method of making curved printing-plates



H. E. HUBBARD. METHOD OF MAKING CURVED PRINTING PLATES.

APPLICATION FILED AUG-19,1918.

Patented July 19, 1921a.

OFFlC.

HENRY E. HUBBARD, OF OAK PARK, ILLINOIS, ASSIGNOR TO ADDRESSOGRAPH COM- IPANY, OF CHICAGO, ILLINOIS, A CORPORATION OF ILLINOIS.

METHOD OF MAKING CURVED PRINTING-PLATES.

Specification of Letters Patent.

Patented July 19, 1921.

Original application filed March 8, 1915, Serial No. 12,817. Divided andthis application filed August 19, 1918. Serial No. 250,601.

To all whom it may concern:

Be it known that LIIENRY E. HUBBARD, a citizen of the United States, residing at Oak Park, in the county of Cook and State of Illinois, have invented certain new and useful Improvements in .Methods of Making Curved Printing-Plates, of which the following is a specification.

This invention relates to a method or making curved metal printing plates, the application being a division of my co-pending application, Serial No. 12,817, tiled March 8, 1915, and patented August 20, 1918, No. 1,276,532.

It is the object of my invention to provide a method of making curved metal printing plates in a simple and 'eiiioient' manner, the curving being etlected without distorting the printing characters thereon.

Further objects and advantages of my invention will be apparent as it is better understood by reference to the following specification when read in connection with the accompanying drawing illustrating the preferred embodiment thereof, in which Figure 1 is view in perspective of a metal blank scored in a plurality of parallel lines as in the first step of my method;

Fig. 2 is a view in perspective of the same blank having a plurality of printing characters struck up from the body thereof;

Fig. 3 is a view in perspective of the plate after the curving operation.

Fig. l is an end elevation of the curved plate, and

Fig. 5 is a sectional view illustrating a portion of a suitable apparatus for curving the plates.

The use of printing plates having characters struck up from the body of a sheet metal blank has been a recent development of the printing art. Methods and means for striking up printing characters from sheet metal blanks have been perfected and are in commercial. use. The graphotype is an example of a machine adapted for use in preparing such plates and reference is made to the patent to Duncan No. 955,116 dated April 12, 1,910, which illustrates one type of such a machine.

Inasmuch as printing machines having cylindrical beds are among the most efiicient known, it is desirable to provide a method of preparing curved printing plates of the character above described adapted to be mounted upon the cylindrical beds of such machines. Considerable difiiculty has, however, been experienced' in producing a satis factory curved printing plate for the reason that it is desirable to strike up the printing characters before the plate is curved and during the curving operation the characters are liable to distortion. A further ditliculty has been experienced in bending the plate to the desired curvature and applicant has devised the present method to overcome the various difficulties encountered.

Referring to Fig. 1 of the drawing, 5 inclicates generally a blank sheet metal plate which is first prepared by scoring the surface thereof along a plurality of lines 6 extending longitudinally of the plate. The plate is then placed in a suitable machine, such as the graphotype which need not be here described, and lines of printing characters 7, (Fig. 2) are struck up from the surface of the platev between the lines of scoring. It is to be understood that the characters shown in Fig. 2 are merely illustrative and that normally the surface of the plate between the lines of scoring will be more or less filled with printing characters. lVhen the above operations have been completed the fiat printing plate is ready for the curving operation which may be carried out in any suitable machine although the structure illustrated in Fig. is best adapted for the purpose.

Referring to Fig. 5, a bed 8 is provided with a conveXly curved face 9, the radius of curvature being that to which the plate is to be bent, and the width of the bed being substantially equal to the width of the printing plate to be treated. A presser head 10 is provided with a platen 11 having a facing 12 of yielding 0r resilient material such as rubber. V The presser head 10 may be brought into contiguous relation with the plate 5 on the bed 8 by suitable mechanism which need not be here described to force the resilient facing between the lines of printing characters and into engagement with the printing plate 5. The plate is bent, along the scored lines 6 and without distorting the printing characters 7, to the curvature of the bed 8, and when the pressure is'withd'rawn the plate is found to be permanently bent to the desired curvature;

It will be noted from an inspection of Fig. 5 that during the pressing operation the printing plate is rigidly supported with its under side cooperating with the curved face 9 of the bed 8. Theyielding 0r resilient facing 12 engages the printing surface of the plate and presses downward between the printing characters so that thepressure is exerted evenly over the entire surface of the printing plate. Applying pressure in this way for the bending operation is believed to be very desirable,.if not essential, to do the work properly, and I find that thereby I am enabled to produce a perfectly curved plate without distortion of the printing characters and with a minimum of effort. This yielding or resilient pressure permits the bending of the metal only at the score lines, while the faces of the characters are left fiat and each face is disposed tangentially to an are concentric with the center of curvature of the plate so that clear and distinct impressions will be made by each printing character on the plate. In order to properly bend a printing plate so that all the type characters thereon will produce a clear and distinct impression, it is necessary, as pointed out in my Patent No. 1,276,532, that the pressure be applied simultaneously throughout the entire surface of the plate, so that the plate will bend only at the score lines and the intermediate portions thereof hearing printing characters will be maintained in their originalcondition. This result has been accomplished by employing the yieldthey may be readily fitted ontothe printing cylinder where they closely engage without buckling or other distortion.

It will beapparent that I have devised a novel series of steps in a method for making curved printing plates comprising scoring a sheet metal plate, striking up raised characters from the surface thereof and bending the plate to the desired curvature, the bending occurring at the lines of scoring. It will be further apparent that the plate resulting from my method is superior in printing qualities to any plate heretofore suggested because the printing characters retain their original flat faces tangential to a circle concentric with the curvature ofthe plate.

Various changes may be made in the steps of the method, as above defined, as well as in the apparatus used, without departing from the spirit and scope of the invention or sacrificing any of its material advantages, the outline hereinbefo're recited being merely the preferred embodiment of the invention.

I claim:

1. The method of making curved printing plates which consists of striking up printing characters on one face of a plate and then subjecting the plate to pressure between concavo-convex surfaces, the surface'contacting with said characters being of resilient ma terial. r

2. The step in the formation of a printing plate having a plurality of printing faces angularly disposed with relation to each other,.which consists in scoring the plate on a plurality of parallel lines and compressing the plate between concentrically curved surfaces adapted to be used irrespective of the number of printing faces to be produced on the plate. v V

3. A method of making curved printing plates which comprises scoring the plate on one side thereof in a plurality of parallel lines, striking up printing characters from the plate between said score lines, and then applying yielding pressure to the plate and at the same time forcing a resilient facing 'against the type side of-the plate and into the cavities of the type characters and into the spaces between the type characters to preserve the type characters from distortion and permit the plate to be bent only along the score lines.

4. The method of forming a curved printing plate having a plurality of flat printing faces, which is characterized by the use of .concavo-convex surfaces between which the applying pressure through a concentrically curved body having a resilient face presented to the top side of the plate.

6. The method ofmaking a curved printing plate which consists in scoring the plate on one face thereof and on a plurality of plate being sufficient to bend it along the parallel linefs, stgiking up prlntingi characscore lines only.

ters on said ace etweensaid score lnes and then subjecting the plate to pressure between HENRY HUBBARD 5 concentrically curved surfaces, the surface Witnesses:

contacting with said face being of resilient E. H. MERCHANT,

material and the pressure applied to said NM. 0. BELT. 

